Fish ($350 eff) opens to $20 in UTG+1, 2 calls, I call in SB with T♦ T♥ , BB calls.

Flop: 89Tr Pot $100 Checked to fish, fish bets $35, folds to me, I call, BB CRs to $150, fish folds, it's on me

Fish telegraphs his hand strength via bet size so he probably didn't have much. BB is a young grinder, don't know much about him, he just sat down 5 mins ago, he has $1500, I cover.

1. What do you think of my decision to flat fish's bet?

2. What do you do now, what's your plan for the hand and why?